The present invention relates in general to devices and methods for controlling the operation of handpieces during ophthalmic surgery and more particularly concerns control of irrigation, aspiration, phaco-emulsification, and vitrector cutting during surgery to remove cataracts.
During cataract surgery it is necessary to remove an opaque lens from the patient's eye. One method of removing the lens is known as phaco-emulsification. First, a small incision is made on the side of the cornea and the lens membrane is punctured. Then, the lens is ultrasonically shattered using a phaco-emulsification instrument that irrigates the eye and aspirates particles of the lens as the lens is being emulsified. A silicone replacement lens is then folded and fed through the small corneal incision. Alternatively, the opening is enlarged to a size sufficient to permit insertion of a conventional hard lens.
The handpiece used during the incision of the cornea and puncturing of the lens membrane and the handpiece used during phaco-emulsification are typically controlled by a control module in conjunction with a foot pedal module. The foot pedal module provides linear control over the aspiration rate, the intensity of power applied to the phaco handpiece, etc. within parameters (e.g., maxima and minima) selected by a variety of control knobs or buttons on the control module. The control module includes a variety of displays for displaying the aspiration rate, vacuum pressure during aspiration, power applied to the phaco handpiece, etc. The control module also includes circuitry, responsive to the control knobs or buttons on the control module and responsive to the foot pedal module, for controlling an aspiration pump, vacuum pressure regulator, phaco-power driver, etc. and for controlling the displays on the control module.